// Copyright (c) 1999, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Author: Ray Sidney
//
// This file contains #include information about logging-related stuff.
// Pretty much everybody needs to #include this file so that they can
// log various happenings.
//
#ifndef _LOGGING_H_
#define _LOGGING_H_

#include <errno.h>
#include <string.h>
#include <time.h>
#include <iosfwd>
#include <ostream>
#include <sstream>
#include <string>
#if 1
#include <unistd.h>
#endif
#include <vector>

#if defined(_MSC_VER)
#define GLOG_MSVC_PUSH_DISABLE_WARNING(n) __pragma(warning(push)) \
    __pragma(warning(disable : n))
#define GLOG_MSVC_POP_WARNING() __pragma(warning(pop))
#else
#define GLOG_MSVC_PUSH_DISABLE_WARNING(n)
#define GLOG_MSVC_POP_WARNING()
#endif

// Annoying stuff for windows -- makes sure clients can import these functions
#ifndef GOOGLE_GLOG_DLL_DECL
#if defined(_WIN32) && !defined(__CYGWIN__)
#define GOOGLE_GLOG_DLL_DECL __declspec(dllimport)
#else
#define GOOGLE_GLOG_DLL_DECL
#endif
#endif

// We care a lot about number of bits things take up.  Unfortunately,
// systems define their bit-specific ints in a lot of different ways.
// We use our own way, and have a typedef to get there.
// Note: these commands below may look like "#if 1" or "#if 0", but
// that's because they were constructed that way at ./configure time.
// Look at logging.h.in to see how they're calculated (based on your config).
#if 1
#include <stdint.h> // the normal place uint16_t is defined
#endif
#if 1
#include <sys/types.h> // the normal place u_int16_t is defined
#endif
#if 1
#include <inttypes.h> // a third place for uint16_t or u_int16_t
#endif

#if 0
#include <gflags/gflags.h>
#endif

namespace google
{

#if 1 // the C99 format
  typedef int32_t int32;
  typedef uint32_t uint32;
  typedef int64_t int64;
  typedef uint64_t uint64;
#elif 1 // the BSD format
  typedef int32_t int32;
  typedef u_int32_t uint32;
  typedef int64_t int64;
  typedef u_int64_t uint64;
#elif 0 // the windows (vc7) format
  typedef __int32 int32;
  typedef unsigned __int32 uint32;
  typedef __int64 int64;
  typedef unsigned __int64 uint64;
#else
#error Do not know how to define a 32-bit integer quantity on your system
#endif

}

// The global value of GOOGLE_STRIP_LOG. All the messages logged to
// LOG(XXX) with severity less than GOOGLE_STRIP_LOG will not be displayed.
// If it can be determined at compile time that the message will not be
// printed, the statement will be compiled out.
//
// Example: to strip out all INFO and WARNING messages, use the value
// of 2 below. To make an exception for WARNING messages from a single
// file, add "#define GOOGLE_STRIP_LOG 1" to that file _before_ including
// base/logging.h
#ifndef GOOGLE_STRIP_LOG
#define GOOGLE_STRIP_LOG 0
#endif

// GCC can be told that a certain branch is not likely to be taken (for
// instance, a CHECK failure), and use that information in static analysis.
// Giving it this information can help it optimize for the common case in
// the absence of better information (ie. -fprofile-arcs).
//
#ifndef GOOGLE_PREDICT_BRANCH_NOT_TAKEN
#if 1
#define GOOGLE_PREDICT_BRANCH_NOT_TAKEN(x) (__builtin_expect(x, 0))
#else
#define GOOGLE_PREDICT_BRANCH_NOT_TAKEN(x) x
#endif
#endif

#ifndef GOOGLE_PREDICT_FALSE
#if 1
#define GOOGLE_PREDICT_FALSE(x) (__builtin_expect(x, 0))
#else
#define GOOGLE_PREDICT_FALSE(x) x
#endif
#endif

#ifndef GOOGLE_PREDICT_TRUE
#if 1
#define GOOGLE_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
#else
#define GOOGLE_PREDICT_TRUE(x) x
#endif
#endif

// Make a bunch of macros for logging.  The way to log things is to stream
// things to LOG(<a particular severity level>).  E.g.,
//
//   LOG(INFO) << "Found " << num_cookies << " cookies";
//
// You can capture log messages in a string, rather than reporting them
// immediately:
//
//   vector<string> errors;
//   LOG_STRING(ERROR, &errors) << "Couldn't parse cookie #" << cookie_num;
//
// This pushes back the new error onto 'errors'; if given a NULL pointer,
// it reports the error via LOG(ERROR).
//
// You can also do conditional logging:
//
//   LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
//
// You can also do occasional logging (log every n'th occurrence of an
// event):
//
//   LOG_EVERY_N(INFO, 10) << "Got the " << google::COUNTER << "th cookie";
//
// The above will cause log messages to be output on the 1st, 11th, 21st, ...
// times it is executed.  Note that the special google::COUNTER value is used
// to identify which repetition is happening.
//
// You can also do occasional conditional logging (log every n'th
// occurrence of an event, when condition is satisfied):
//
//   LOG_IF_EVERY_N(INFO, (size > 1024), 10) << "Got the " << google::COUNTER
//                                           << "th big cookie";
//
// You can log messages the first N times your code executes a line. E.g.
//
//   LOG_FIRST_N(INFO, 20) << "Got the " << google::COUNTER << "th cookie";
//
// Outputs log messages for the first 20 times it is executed.
//
// Analogous SYSLOG, SYSLOG_IF, and SYSLOG_EVERY_N macros are available.
// These log to syslog as well as to the normal logs.  If you use these at
// all, you need to be aware that syslog can drastically reduce performance,
// especially if it is configured for remote logging!  Don't use these
// unless you fully understand this and have a concrete need to use them.
// Even then, try to minimize your use of them.
//
// There are also "debug mode" logging macros like the ones above:
//
//   DLOG(INFO) << "Found cookies";
//
//   DLOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
//
//   DLOG_EVERY_N(INFO, 10) << "Got the " << google::COUNTER << "th cookie";
//
// All "debug mode" logging is compiled away to nothing for non-debug mode
// compiles.
//
// We also have
//
//   LOG_ASSERT(assertion);
//   DLOG_ASSERT(assertion);
//
// which is syntactic sugar for {,D}LOG_IF(FATAL, assert fails) << assertion;
//
// There are "verbose level" logging macros.  They look like
//
//   VLOG(1) << "I'm printed when you run the program with --v=1 or more";
//   VLOG(2) << "I'm printed when you run the program with --v=2 or more";
//
// These always log at the INFO log level (when they log at all).
// The verbose logging can also be turned on module-by-module.  For instance,
//    --vmodule=mapreduce=2,file=1,gfs*=3 --v=0
// will cause:
//   a. VLOG(2) and lower messages to be printed from mapreduce.{h,cc}
//   b. VLOG(1) and lower messages to be printed from file.{h,cc}
//   c. VLOG(3) and lower messages to be printed from files prefixed with "gfs"
//   d. VLOG(0) and lower messages to be printed from elsewhere
//
// The wildcarding functionality shown by (c) supports both '*' (match
// 0 or more characters) and '?' (match any single character) wildcards.
//
// There's also VLOG_IS_ON(n) "verbose level" condition macro. To be used as
//
//   if (VLOG_IS_ON(2)) {
//     // do some logging preparation and logging
//     // that can't be accomplished with just VLOG(2) << ...;
//   }
//
// There are also VLOG_IF, VLOG_EVERY_N and VLOG_IF_EVERY_N "verbose level"
// condition macros for sample cases, when some extra computation and
// preparation for logs is not needed.
//   VLOG_IF(1, (size > 1024))
//      << "I'm printed when size is more than 1024 and when you run the "
//         "program with --v=1 or more";
//   VLOG_EVERY_N(1, 10)
//      << "I'm printed every 10th occurrence, and when you run the program "
//         "with --v=1 or more. Present occurence is " << google::COUNTER;
//   VLOG_IF_EVERY_N(1, (size > 1024), 10)
//      << "I'm printed on every 10th occurence of case when size is more "
//         " than 1024, when you run the program with --v=1 or more. ";
//         "Present occurence is " << google::COUNTER;
//
// The supported severity levels for macros that allow you to specify one
// are (in increasing order of severity) INFO, WARNING, ERROR, and FATAL.
// Note that messages of a given severity are logged not only in the
// logfile for that severity, but also in all logfiles of lower severity.
// E.g., a message of severity FATAL will be logged to the logfiles of
// severity FATAL, ERROR, WARNING, and INFO.
//
// There is also the special severity of DFATAL, which logs FATAL in
// debug mode, ERROR in normal mode.
//
// Very important: logging a message at the FATAL severity level causes
// the program to terminate (after the message is logged).
//
// Unless otherwise specified, logs will be written to the filename
// "<program name>.<hostname>.<user name>.log.<severity level>.", followed
// by the date, time, and pid (you can't prevent the date, time, and pid
// from being in the filename).
//
// The logging code takes two flags:
//     --v=#           set the verbose level
//     --logtostderr   log all the messages to stderr instead of to logfiles

// LOG LINE PREFIX FORMAT
//
// Log lines have this form:
//
//     Lmmdd hh:mm:ss.uuuuuu threadid file:line] msg...
//
// where the fields are defined as follows:
//
//   L                A single character, representing the log level
//                    (eg 'I' for INFO)
//   mm               The month (zero padded; ie May is '05')
//   dd               The day (zero padded)
//   hh:mm:ss.uuuuuu  Time in hours, minutes and fractional seconds
//   threadid         The space-padded thread ID as returned by GetTID()
//                    (this matches the PID on Linux)
//   file             The file name
//   line             The line number
//   msg              The user-supplied message
//
// Example:
//
//   I1103 11:57:31.739339 24395 google.cc:2341] Command line: ./some_prog
//   I1103 11:57:31.739403 24395 google.cc:2342] Process id 24395
//
// NOTE: although the microseconds are useful for comparing events on
// a single machine, clocks on different machines may not be well
// synchronized.  Hence, use caution when comparing the low bits of
// timestamps from different machines.

#ifndef DECLARE_VARIABLE
#define MUST_UNDEF_GFLAGS_DECLARE_MACROS
#define DECLARE_VARIABLE(type, shorttype, name, tn) \
  namespace fL##shorttype                           \
  {                                                 \
    extern GOOGLE_GLOG_DLL_DECL type FLAGS_##name;  \
  }                                                 \
  using fL##shorttype::FLAGS_##name

// bool specialization
#define DECLARE_bool(name) \
  DECLARE_VARIABLE(bool, B, name, bool)

// int32 specialization
#define DECLARE_int32(name) \
  DECLARE_VARIABLE(google::int32, I, name, int32)

// Special case for string, because we have to specify the namespace
// std::string, which doesn't play nicely with our FLAG__namespace hackery.
#define DECLARE_string(name)                               \
  namespace fLS                                            \
  {                                                        \
    extern GOOGLE_GLOG_DLL_DECL std::string &FLAGS_##name; \
  }                                                        \
  using fLS::FLAGS_##name
#endif

// Set whether log messages go to stderr instead of logfiles
DECLARE_bool(logtostderr);

// Set whether log messages go to stderr in addition to logfiles.
DECLARE_bool(alsologtostderr);

// Set color messages logged to stderr (if supported by terminal).
DECLARE_bool(colorlogtostderr);

// Log messages at a level >= this flag are automatically sent to
// stderr in addition to log files.
DECLARE_int32(stderrthreshold);

// Set whether the log prefix should be prepended to each line of output.
DECLARE_bool(log_prefix);

// Log messages at a level <= this flag are buffered.
// Log messages at a higher level are flushed immediately.
DECLARE_int32(logbuflevel);

// Sets the maximum number of seconds which logs may be buffered for.
DECLARE_int32(logbufsecs);

// Log suppression level: messages logged at a lower level than this
// are suppressed.
DECLARE_int32(minloglevel);

// If specified, logfiles are written into this directory instead of the
// default logging directory.
DECLARE_string(log_dir);

// Set the log file mode.
DECLARE_int32(logfile_mode);

// Sets the path of the directory into which to put additional links
// to the log files.
DECLARE_string(log_link);

DECLARE_int32(v); // in vlog_is_on.cc

// Sets the maximum log file size (in MB).
DECLARE_int32(max_log_size);

// Sets whether to avoid logging to the disk if the disk is full.
DECLARE_bool(stop_logging_if_full_disk);

#ifdef MUST_UNDEF_GFLAGS_DECLARE_MACROS
#undef MUST_UNDEF_GFLAGS_DECLARE_MACROS
#undef DECLARE_VARIABLE
#undef DECLARE_bool
#undef DECLARE_int32
#undef DECLARE_string
#endif

// Log messages below the GOOGLE_STRIP_LOG level will be compiled away for
// security reasons. See LOG(severtiy) below.

// A few definitions of macros that don't generate much code.  Since
// LOG(INFO) and its ilk are used all over our code, it's
// better to have compact code for these operations.

#if GOOGLE_STRIP_LOG == 0
#define COMPACT_GOOGLE_LOG_INFO google::LogMessage( \
    __FILE__, __LINE__)
#define LOG_TO_STRING_INFO(message) google::LogMessage( \
    __FILE__, __LINE__, google::GLOG_INFO, message)
#else
#define COMPACT_GOOGLE_LOG_INFO google::NullStream()
#define LOG_TO_STRING_INFO(message) google::NullStream()
#endif

#if GOOGLE_STRIP_LOG <= 1
#define COMPACT_GOOGLE_LOG_WARNING google::LogMessage( \
    __FILE__, __LINE__, google::GLOG_WARNING)
#define LOG_TO_STRING_WARNING(message) google::LogMessage( \
    __FILE__, __LINE__, google::GLOG_WARNING, message)
#else
#define COMPACT_GOOGLE_LOG_WARNING google::NullStream()
#define LOG_TO_STRING_WARNING(message) google::NullStream()
#endif

#if GOOGLE_STRIP_LOG <= 2
#define COMPACT_GOOGLE_LOG_ERROR google::LogMessage( \
    __FILE__, __LINE__, google::GLOG_ERROR)
#define LOG_TO_STRING_ERROR(message) google::LogMessage( \
    __FILE__, __LINE__, google::GLOG_ERROR, message)
#else
#define COMPACT_GOOGLE_LOG_ERROR google::NullStream()
#define LOG_TO_STRING_ERROR(message) google::NullStream()
#endif

#if GOOGLE_STRIP_LOG <= 3
#define COMPACT_GOOGLE_LOG_FATAL google::LogMessageFatal( \
    __FILE__, __LINE__)
#define LOG_TO_STRING_FATAL(message) google::LogMessage( \
    __FILE__, __LINE__, google::GLOG_FATAL, message)
#else
#define COMPACT_GOOGLE_LOG_FATAL google::NullStreamFatal()
#define LOG_TO_STRING_FATAL(message) google::NullStreamFatal()
#endif

// For DFATAL, we want to use LogMessage (as opposed to
// LogMessageFatal), to be consistent with the original behavior.
#ifdef NDEBUG
#define COMPACT_GOOGLE_LOG_DFATAL COMPACT_GOOGLE_LOG_ERROR
#elif GOOGLE_STRIP_LOG <= 3
#define COMPACT_GOOGLE_LOG_DFATAL google::LogMessage( \
    __FILE__, __LINE__, google::GLOG_FATAL)
#else
#define COMPACT_GOOGLE_LOG_DFATAL google::NullStreamFatal()
#endif

#define GOOGLE_LOG_INFO(counter) google::LogMessage(__FILE__, __LINE__, google::GLOG_INFO, counter, &google::LogMessage::SendToLog)
#define SYSLOG_INFO(counter)                                         \
  google::LogMessage(__FILE__, __LINE__, google::GLOG_INFO, counter, \
                     &google::LogMessage::SendToSyslogAndLog)
#define GOOGLE_LOG_WARNING(counter)                                     \
  google::LogMessage(__FILE__, __LINE__, google::GLOG_WARNING, counter, \
                     &google::LogMessage::SendToLog)
#define SYSLOG_WARNING(counter)                                         \
  google::LogMessage(__FILE__, __LINE__, google::GLOG_WARNING, counter, \
                     &google::LogMessage::SendToSyslogAndLog)
#define GOOGLE_LOG_ERROR(counter)                                     \
  google::LogMessage(__FILE__, __LINE__, google::GLOG_ERROR, counter, \
                     &google::LogMessage::SendToLog)
#define SYSLOG_ERROR(counter)                                         \
  google::LogMessage(__FILE__, __LINE__, google::GLOG_ERROR, counter, \
                     &google::LogMessage::SendToSyslogAndLog)
#define GOOGLE_LOG_FATAL(counter)                                     \
  google::LogMessage(__FILE__, __LINE__, google::GLOG_FATAL, counter, \
                     &google::LogMessage::SendToLog)
#define SYSLOG_FATAL(counter)                                         \
  google::LogMessage(__FILE__, __LINE__, google::GLOG_FATAL, counter, \
                     &google::LogMessage::SendToSyslogAndLog)
#define GOOGLE_LOG_DFATAL(counter)                                      \
  google::LogMessage(__FILE__, __LINE__, google::DFATAL_LEVEL, counter, \
                     &google::LogMessage::SendToLog)
#define SYSLOG_DFATAL(counter)                                          \
  google::LogMessage(__FILE__, __LINE__, google::DFATAL_LEVEL, counter, \
                     &google::LogMessage::SendToSyslogAndLog)

#if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__) || defined(__CYGWIN32__)
// A very useful logging macro to log windows errors:
#define LOG_SYSRESULT(result)                                              \
  if (FAILED(HRESULT_FROM_WIN32(result)))                                  \
  {                                                                        \
    LPSTR message = NULL;                                                  \
    LPSTR msg = reinterpret_cast<LPSTR>(&message);                         \
    DWORD message_length = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | \
                                              FORMAT_MESSAGE_FROM_SYSTEM,  \
                                          0, result, 0, msg, 100, NULL);   \
    if (message_length > 0)                                                \
    {                                                                      \
      google::LogMessage(__FILE__, __LINE__, google::GLOG_ERROR, 0,        \
                         &google::LogMessage::SendToLog)                   \
              .stream()                                                    \
          << reinterpret_cast<const char *>(message);                      \
      LocalFree(message);                                                  \
    }                                                                      \
  }
#endif

// We use the preprocessor's merging operator, "##", so that, e.g.,
// LOG(INFO) becomes the token GOOGLE_LOG_INFO.  There's some funny
// subtle difference between ostream member streaming functions (e.g.,
// ostream::operator<<(int) and ostream non-member streaming functions
// (e.g., ::operator<<(ostream&, string&): it turns out that it's
// impossible to stream something like a string directly to an unnamed
// ostream. We employ a neat hack by calling the stream() member
// function of LogMessage which seems to avoid the problem.
#define LOG(severity) COMPACT_GOOGLE_LOG_##severity.stream()
#define SYSLOG(severity) SYSLOG_##severity(0).stream()

namespace google
{

// They need the definitions of integer types.
#include "log_severity.h"
#include "vlog_is_on.h"

  // Initialize google's logging library. You will see the program name
  // specified by argv0 in log outputs.
  GOOGLE_GLOG_DLL_DECL void InitGoogleLogging(const char *argv0);

  // Shutdown google's logging library.
  GOOGLE_GLOG_DLL_DECL void ShutdownGoogleLogging();

  // Install a function which will be called after LOG(FATAL).
  GOOGLE_GLOG_DLL_DECL void InstallFailureFunction(void (*fail_func)());

  class LogSink; // defined below

// If a non-NULL sink pointer is given, we push this message to that sink.
// For LOG_TO_SINK we then do normal LOG(severity) logging as well.
// This is useful for capturing messages and passing/storing them
// somewhere more specific than the global log of the process.
// Argument types:
//   LogSink* sink;
//   LogSeverity severity;
// The cast is to disambiguate NULL arguments.
#define LOG_TO_SINK(sink, severity)               \
  google::LogMessage(                             \
      __FILE__, __LINE__,                         \
      google::GLOG_##severity,                    \
      static_cast<google::LogSink *>(sink), true) \
      .stream()
#define LOG_TO_SINK_BUT_NOT_TO_LOGFILE(sink, severity) \
  google::LogMessage(                                  \
      __FILE__, __LINE__,                              \
      google::GLOG_##severity,                         \
      static_cast<google::LogSink *>(sink), false)     \
      .stream()

// If a non-NULL string pointer is given, we write this message to that string.
// We then do normal LOG(severity) logging as well.
// This is useful for capturing messages and storing them somewhere more
// specific than the global log of the process.
// Argument types:
//   string* message;
//   LogSeverity severity;
// The cast is to disambiguate NULL arguments.
// NOTE: LOG(severity) expands to LogMessage().stream() for the specified
// severity.
#define LOG_TO_STRING(severity, message) \
  LOG_TO_STRING_##severity(static_cast<string *>(message)).stream()

// If a non-NULL pointer is given, we push the message onto the end
// of a vector of strings; otherwise, we report it with LOG(severity).
// This is handy for capturing messages and perhaps passing them back
// to the caller, rather than reporting them immediately.
// Argument types:
//   LogSeverity severity;
//   vector<string> *outvec;
// The cast is to disambiguate NULL arguments.
#define LOG_STRING(severity, outvec) \
  LOG_TO_STRING_##severity(static_cast<std::vector<std::string> *>(outvec)).stream()

#define LOG_IF(severity, condition) \
  !(condition) ? (void)0 : google::LogMessageVoidify() & LOG(severity)
#define SYSLOG_IF(severity, condition) \
  !(condition) ? (void)0 : google::LogMessageVoidify() & SYSLOG(severity)

#define LOG_ASSERT(condition) \
  LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition
#define SYSLOG_ASSERT(condition) \
  SYSLOG_IF(FATAL, !(condition)) << "Assert failed: " #condition

// CHECK dies with a fatal error if condition is not true.  It is *not*
// controlled by NDEBUG, so the check will be executed regardless of
// compilation mode.  Therefore, it is safe to do things like:
//    CHECK(fp->Write(x) == 4)
#define CHECK(condition)                                       \
  LOG_IF(FATAL, GOOGLE_PREDICT_BRANCH_NOT_TAKEN(!(condition))) \
      << "Check failed: " #condition " "

  // A container for a string pointer which can be evaluated to a bool -
  // true iff the pointer is NULL.
  struct CheckOpString
  {
    CheckOpString(std::string *str) : str_(str) {}
    // No destructor: if str_ is non-NULL, we're about to LOG(FATAL),
    // so there's no point in cleaning up str_.
    operator bool() const
    {
      return GOOGLE_PREDICT_BRANCH_NOT_TAKEN(str_ != NULL);
    }
    std::string *str_;
  };

  // Function is overloaded for integral types to allow static const
  // integrals declared in classes and not defined to be used as arguments to
  // CHECK* macros. It's not encouraged though.
  template <class T>
  inline const T &GetReferenceableValue(const T &t) { return t; }
  inline char GetReferenceableValue(char t) { return t; }
  inline unsigned char GetReferenceableValue(unsigned char t) { return t; }
  inline signed char GetReferenceableValue(signed char t) { return t; }
  inline short GetReferenceableValue(short t) { return t; }
  inline unsigned short GetReferenceableValue(unsigned short t) { return t; }
  inline int GetReferenceableValue(int t) { return t; }
  inline unsigned int GetReferenceableValue(unsigned int t) { return t; }
  inline long GetReferenceableValue(long t) { return t; }
  inline unsigned long GetReferenceableValue(unsigned long t) { return t; }
  inline long long GetReferenceableValue(long long t) { return t; }
  inline unsigned long long GetReferenceableValue(unsigned long long t)
  {
    return t;
  }

  // This is a dummy class to define the following operator.
  struct DummyClassToDefineOperator
  {
  };

}

// Define global operator<< to declare using ::operator<<.
// This declaration will allow use to use CHECK macros for user
// defined classes which have operator<< (e.g., stl_logging.h).
inline std::ostream &operator<<(
    std::ostream &out, const google::DummyClassToDefineOperator &)
{
  return out;
}

namespace google
{

  // This formats a value for a failing CHECK_XX statement.  Ordinarily,
  // it uses the definition for operator<<, with a few special cases below.
  template <typename T>
  inline void MakeCheckOpValueString(std::ostream *os, const T &v)
  {
    (*os) << v;
  }

  // Overrides for char types provide readable values for unprintable
  // characters.
  template <>
  GOOGLE_GLOG_DLL_DECL void MakeCheckOpValueString(std::ostream *os, const char &v);
  template <>
  GOOGLE_GLOG_DLL_DECL void MakeCheckOpValueString(std::ostream *os, const signed char &v);
  template <>
  GOOGLE_GLOG_DLL_DECL void MakeCheckOpValueString(std::ostream *os, const unsigned char &v);

  // Build the error message string. Specify no inlining for code size.
  template <typename T1, typename T2>
  std::string *MakeCheckOpString(const T1 &v1, const T2 &v2, const char *exprtext)
      __attribute__((noinline));

  namespace base
  {
    namespace internal
    {

      // If "s" is less than base_logging::INFO, returns base_logging::INFO.
      // If "s" is greater than base_logging::FATAL, returns
      // base_logging::ERROR.  Otherwise, returns "s".
      LogSeverity NormalizeSeverity(LogSeverity s);

    } // namespace internal

    // A helper class for formatting "expr (V1 vs. V2)" in a CHECK_XX
    // statement.  See MakeCheckOpString for sample usage.  Other
    // approaches were considered: use of a template method (e.g.,
    // base::BuildCheckOpString(exprtext, base::Print<T1>, &v1,
    // base::Print<T2>, &v2), however this approach has complications
    // related to volatile arguments and function-pointer arguments).
    class GOOGLE_GLOG_DLL_DECL CheckOpMessageBuilder
    {
    public:
      // Inserts "exprtext" and " (" to the stream.
      explicit CheckOpMessageBuilder(const char *exprtext);
      // Deletes "stream_".
      ~CheckOpMessageBuilder();
      // For inserting the first variable.
      std::ostream *ForVar1() { return stream_; }
      // For inserting the second variable (adds an intermediate " vs. ").
      std::ostream *ForVar2();
      // Get the result (inserts the closing ")").
      std::string *NewString();

    private:
      std::ostringstream *stream_;
    };

  } // namespace base

  template <typename T1, typename T2>
  std::string *MakeCheckOpString(const T1 &v1, const T2 &v2, const char *exprtext)
  {
    base::CheckOpMessageBuilder comb(exprtext);
    MakeCheckOpValueString(comb.ForVar1(), v1);
    MakeCheckOpValueString(comb.ForVar2(), v2);
    return comb.NewString();
  }

// Helper functions for CHECK_OP macro.
// The (int, int) specialization works around the issue that the compiler
// will not instantiate the template version of the function on values of
// unnamed enum type - see comment below.
#define DEFINE_CHECK_OP_IMPL(name, op)                                 \
  template <typename T1, typename T2>                                  \
  inline std::string *name##Impl(const T1 &v1, const T2 &v2,           \
                                 const char *exprtext)                 \
  {                                                                    \
    if (GOOGLE_PREDICT_TRUE(v1 op v2))                                 \
      return NULL;                                                     \
    else                                                               \
      return MakeCheckOpString(v1, v2, exprtext);                      \
  }                                                                    \
  inline std::string *name##Impl(int v1, int v2, const char *exprtext) \
  {                                                                    \
    return name##Impl<int, int>(v1, v2, exprtext);                     \
  }

  // We use the full name Check_EQ, Check_NE, etc. in case the file including
  // base/logging.h provides its own #defines for the simpler names EQ, NE, etc.
  // This happens if, for example, those are used as token names in a
  // yacc grammar.
  DEFINE_CHECK_OP_IMPL(Check_EQ, ==) // Compilation error with CHECK_EQ(NULL, x)?
  DEFINE_CHECK_OP_IMPL(Check_NE, !=) // Use CHECK(x == NULL) instead.
  DEFINE_CHECK_OP_IMPL(Check_LE, <=)
  DEFINE_CHECK_OP_IMPL(Check_LT, <)
  DEFINE_CHECK_OP_IMPL(Check_GE, >=)
  DEFINE_CHECK_OP_IMPL(Check_GT, >)
#undef DEFINE_CHECK_OP_IMPL

  // Helper macro for binary operators.
  // Don't use this macro directly in your code, use CHECK_EQ et al below.

#if defined(STATIC_ANALYSIS)
// Only for static analysis tool to know that it is equivalent to assert
#define CHECK_OP_LOG(name, op, val1, val2, log) CHECK((val1)op(val2))
#elif !defined(NDEBUG)
  // In debug mode, avoid constructing CheckOpStrings if possible,
  // to reduce the overhead of CHECK statments by 2x.
  // Real DCHECK-heavy tests have seen 1.5x speedups.

  // The meaning of "string" might be different between now and
  // when this macro gets invoked (e.g., if someone is experimenting
  // with other string implementations that get defined after this
  // file is included).  Save the current meaning now and use it
  // in the macro.
  typedef std::string _Check_string;
#define CHECK_OP_LOG(name, op, val1, val2, log)       \
  while (google::_Check_string *_result =             \
             google::Check##name##Impl(               \
                 google::GetReferenceableValue(val1), \
                 google::GetReferenceableValue(val2), \
                 #val1 " " #op " " #val2))            \
  log(__FILE__, __LINE__,                             \
      google::CheckOpString(_result))                 \
      .stream()
#else
// In optimized mode, use CheckOpString to hint to compiler that
// the while condition is unlikely.
#define CHECK_OP_LOG(name, op, val1, val2, log)       \
  while (google::CheckOpString _result =              \
             google::Check##name##Impl(               \
                 google::GetReferenceableValue(val1), \
                 google::GetReferenceableValue(val2), \
                 #val1 " " #op " " #val2))            \
  log(__FILE__, __LINE__, _result).stream()
#endif // STATIC_ANALYSIS, !NDEBUG

#if GOOGLE_STRIP_LOG <= 3
#define CHECK_OP(name, op, val1, val2) \
  CHECK_OP_LOG(name, op, val1, val2, google::LogMessageFatal)
#else
#define CHECK_OP(name, op, val1, val2) \
  CHECK_OP_LOG(name, op, val1, val2, google::NullStreamFatal)
#endif // STRIP_LOG <= 3

  // Equality/Inequality checks - compare two values, and log a FATAL message
  // including the two values when the result is not as expected.  The values
  // must have operator<<(ostream, ...) defined.
  //
  // You may append to the error message like so:
  //   CHECK_NE(1, 2) << ": The world must be ending!";
  //
  // We are very careful to ensure that each argument is evaluated exactly
  // once, and that anything which is legal to pass as a function argument is
  // legal here.  In particular, the arguments may be temporary expressions
  // which will end up being destroyed at the end of the apparent statement,
  // for example:
  //   CHECK_EQ(string("abc")[1], 'b');
  //
  // WARNING: These don't compile correctly if one of the arguments is a pointer
  // and the other is NULL. To work around this, simply static_cast NULL to the
  // type of the desired pointer.

#define CHECK_EQ(val1, val2) CHECK_OP(_EQ, ==, val1, val2)
#define CHECK_NE(val1, val2) CHECK_OP(_NE, !=, val1, val2)
#define CHECK_LE(val1, val2) CHECK_OP(_LE, <=, val1, val2)
#define CHECK_LT(val1, val2) CHECK_OP(_LT, <, val1, val2)
#define CHECK_GE(val1, val2) CHECK_OP(_GE, >=, val1, val2)
#define CHECK_GT(val1, val2) CHECK_OP(_GT, >, val1, val2)

  // Check that the input is non NULL.  This very useful in constructor
  // initializer lists.

#define CHECK_NOTNULL(val) \
  google::CheckNotNull(__FILE__, __LINE__, "'" #val "' Must be non NULL", (val))

// Helper functions for string comparisons.
// To avoid bloat, the definitions are in logging.cc.
#define DECLARE_CHECK_STROP_IMPL(func, expected)                 \
  GOOGLE_GLOG_DLL_DECL std::string *Check##func##expected##Impl( \
      const char *s1, const char *s2, const char *names);
  DECLARE_CHECK_STROP_IMPL(strcmp, true)
  DECLARE_CHECK_STROP_IMPL(strcmp, false)
  DECLARE_CHECK_STROP_IMPL(strcasecmp, true)
  DECLARE_CHECK_STROP_IMPL(strcasecmp, false)
#undef DECLARE_CHECK_STROP_IMPL

// Helper macro for string comparisons.
// Don't use this macro directly in your code, use CHECK_STREQ et al below.
#define CHECK_STROP(func, op, expected, s1, s2)                        \
  while (google::CheckOpString _result =                               \
             google::Check##func##expected##Impl((s1), (s2),           \
                                                 #s1 " " #op " " #s2)) \
  LOG(FATAL) << *_result.str_

  // String (char*) equality/inequality checks.
  // CASE versions are case-insensitive.
  //
  // Note that "s1" and "s2" may be temporary strings which are destroyed
  // by the compiler at the end of the current "full expression"
  // (e.g. CHECK_STREQ(Foo().c_str(), Bar().c_str())).

#define CHECK_STREQ(s1, s2) CHECK_STROP(strcmp, ==, true, s1, s2)
#define CHECK_STRNE(s1, s2) CHECK_STROP(strcmp, !=, false, s1, s2)
#define CHECK_STRCASEEQ(s1, s2) CHECK_STROP(strcasecmp, ==, true, s1, s2)
#define CHECK_STRCASENE(s1, s2) CHECK_STROP(strcasecmp, !=, false, s1, s2)

#define CHECK_INDEX(I, A) CHECK(I < (sizeof(A) / sizeof(A[0])))
#define CHECK_BOUND(B, A) CHECK(B <= (sizeof(A) / sizeof(A[0])))

#define CHECK_DOUBLE_EQ(val1, val2)                \
  do                                               \
  {                                                \
    CHECK_LE((val1), (val2) + 0.000000000000001L); \
    CHECK_GE((val1), (val2)-0.000000000000001L);   \
  } while (0)

#define CHECK_NEAR(val1, val2, margin)   \
  do                                     \
  {                                      \
    CHECK_LE((val1), (val2) + (margin)); \
    CHECK_GE((val1), (val2) - (margin)); \
  } while (0)

  // perror()..googly style!
  //
  // PLOG() and PLOG_IF() and PCHECK() behave exactly like their LOG* and
  // CHECK equivalents with the addition that they postpend a description
  // of the current state of errno to their output lines.

#define PLOG(severity) GOOGLE_PLOG(severity, 0).stream()

#define GOOGLE_PLOG(severity, counter)                      \
  google::ErrnoLogMessage(                                  \
      __FILE__, __LINE__, google::GLOG_##severity, counter, \
      &google::LogMessage::SendToLog)

#define PLOG_IF(severity, condition) \
  !(condition) ? (void)0 : google::LogMessageVoidify() & PLOG(severity)

// A CHECK() macro that postpends errno if the condition is false. E.g.
//
// if (poll(fds, nfds, timeout) == -1) { PCHECK(errno == EINTR); ... }
#define PCHECK(condition)                                       \
  PLOG_IF(FATAL, GOOGLE_PREDICT_BRANCH_NOT_TAKEN(!(condition))) \
      << "Check failed: " #condition " "

// A CHECK() macro that lets you assert the success of a function that
// returns -1 and sets errno in case of an error. E.g.
//
// CHECK_ERR(mkdir(path, 0700));
//
// or
//
// int fd = open(filename, flags); CHECK_ERR(fd) << ": open " << filename;
#define CHECK_ERR(invocation)                                         \
  PLOG_IF(FATAL, GOOGLE_PREDICT_BRANCH_NOT_TAKEN((invocation) == -1)) \
      << #invocation

// Use macro expansion to create, for each use of LOG_EVERY_N(), static
// variables with the __LINE__ expansion as part of the variable name.
#define LOG_EVERY_N_VARNAME(base, line) LOG_EVERY_N_VARNAME_CONCAT(base, line)
#define LOG_EVERY_N_VARNAME_CONCAT(base, line) base##line

#define LOG_OCCURRENCES LOG_EVERY_N_VARNAME(occurrences_, __LINE__)
#define LOG_OCCURRENCES_MOD_N LOG_EVERY_N_VARNAME(occurrences_mod_n_, __LINE__)

#define SOME_KIND_OF_LOG_EVERY_N(severity, n, what_to_do)           \
  static int LOG_OCCURRENCES = 0, LOG_OCCURRENCES_MOD_N = 0;        \
  ++LOG_OCCURRENCES;                                                \
  if (++LOG_OCCURRENCES_MOD_N > n)                                  \
    LOG_OCCURRENCES_MOD_N -= n;                                     \
  if (LOG_OCCURRENCES_MOD_N == 1)                                   \
  google::LogMessage(                                               \
      __FILE__, __LINE__, google::GLOG_##severity, LOG_OCCURRENCES, \
      &what_to_do)                                                  \
      .stream()

#define SOME_KIND_OF_LOG_IF_EVERY_N(severity, condition, n, what_to_do)       \
  static int LOG_OCCURRENCES = 0, LOG_OCCURRENCES_MOD_N = 0;                  \
  ++LOG_OCCURRENCES;                                                          \
  if (condition &&                                                            \
      ((LOG_OCCURRENCES_MOD_N = (LOG_OCCURRENCES_MOD_N + 1) % n) == (1 % n))) \
  google::LogMessage(                                                         \
      __FILE__, __LINE__, google::GLOG_##severity, LOG_OCCURRENCES,           \
      &what_to_do)                                                            \
      .stream()

#define SOME_KIND_OF_PLOG_EVERY_N(severity, n, what_to_do)          \
  static int LOG_OCCURRENCES = 0, LOG_OCCURRENCES_MOD_N = 0;        \
  ++LOG_OCCURRENCES;                                                \
  if (++LOG_OCCURRENCES_MOD_N > n)                                  \
    LOG_OCCURRENCES_MOD_N -= n;                                     \
  if (LOG_OCCURRENCES_MOD_N == 1)                                   \
  google::ErrnoLogMessage(                                          \
      __FILE__, __LINE__, google::GLOG_##severity, LOG_OCCURRENCES, \
      &what_to_do)                                                  \
      .stream()

#define SOME_KIND_OF_LOG_FIRST_N(severity, n, what_to_do)           \
  static int LOG_OCCURRENCES = 0;                                   \
  if (LOG_OCCURRENCES <= n)                                         \
    ++LOG_OCCURRENCES;                                              \
  if (LOG_OCCURRENCES <= n)                                         \
  google::LogMessage(                                               \
      __FILE__, __LINE__, google::GLOG_##severity, LOG_OCCURRENCES, \
      &what_to_do)                                                  \
      .stream()

  namespace glog_internal_namespace_
  {
    template <bool>
    struct CompileAssert
    {
    };
    struct CrashReason;

    // Returns true if FailureSignalHandler is installed.
    bool IsFailureSignalHandlerInstalled();
  } // namespace glog_internal_namespace_

#define GOOGLE_GLOG_COMPILE_ASSERT(expr, msg) \
  typedef google::glog_internal_namespace_::CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1]

#define LOG_EVERY_N(severity, n)                              \
  GOOGLE_GLOG_COMPILE_ASSERT(google::GLOG_##severity <        \
                                 google::NUM_SEVERITIES,      \
                             INVALID_REQUESTED_LOG_SEVERITY); \
  SOME_KIND_OF_LOG_EVERY_N(severity, (n), google::LogMessage::SendToLog)

#define SYSLOG_EVERY_N(severity, n) \
  SOME_KIND_OF_LOG_EVERY_N(severity, (n), google::LogMessage::SendToSyslogAndLog)

#define PLOG_EVERY_N(severity, n) \
  SOME_KIND_OF_PLOG_EVERY_N(severity, (n), google::LogMessage::SendToLog)

#define LOG_FIRST_N(severity, n) \
  SOME_KIND_OF_LOG_FIRST_N(severity, (n), google::LogMessage::SendToLog)

#define LOG_IF_EVERY_N(severity, condition, n) \
  SOME_KIND_OF_LOG_IF_EVERY_N(severity, (condition), (n), google::LogMessage::SendToLog)

  // We want the special COUNTER value available for LOG_EVERY_X()'ed messages
  enum PRIVATE_Counter
  {
    COUNTER
  };

#ifdef GLOG_NO_ABBREVIATED_SEVERITIES
// wingdi.h defines ERROR to be 0. When we call LOG(ERROR), it gets
// substituted with 0, and it expands to COMPACT_GOOGLE_LOG_0. To allow us
// to keep using this syntax, we define this macro to do the same thing
// as COMPACT_GOOGLE_LOG_ERROR.
#define COMPACT_GOOGLE_LOG_0 COMPACT_GOOGLE_LOG_ERROR
#define SYSLOG_0 SYSLOG_ERROR
#define LOG_TO_STRING_0 LOG_TO_STRING_ERROR
  // Needed for LOG_IS_ON(ERROR).
  const LogSeverity GLOG_0 = GLOG_ERROR;
#else
// Users may include windows.h after logging.h without
// GLOG_NO_ABBREVIATED_SEVERITIES nor WIN32_LEAN_AND_MEAN.
// For this case, we cannot detect if ERROR is defined before users
// actually use ERROR. Let's make an undefined symbol to warn users.
#define GLOG_ERROR_MSG ERROR_macro_is_defined_Define_GLOG_NO_ABBREVIATED_SEVERITIES_before_including_logging_h_See_the_document_for_detail
#define COMPACT_GOOGLE_LOG_0 GLOG_ERROR_MSG
#define SYSLOG_0 GLOG_ERROR_MSG
#define LOG_TO_STRING_0 GLOG_ERROR_MSG
#define GLOG_0 GLOG_ERROR_MSG
#endif

  // Plus some debug-logging macros that get compiled to nothing for production

#ifndef NDEBUG

#define DLOG(severity) LOG(severity)
#define DVLOG(verboselevel) VLOG(verboselevel)
#define DLOG_IF(severity, condition) LOG_IF(severity, condition)
#define DLOG_EVERY_N(severity, n) LOG_EVERY_N(severity, n)
#define DLOG_IF_EVERY_N(severity, condition, n) \
  LOG_IF_EVERY_N(severity, condition, n)
#define DLOG_ASSERT(condition) LOG_ASSERT(condition)

// debug-only checking.  not executed in NDEBUG mode.
#define DCHECK(condition) CHECK(condition)
#define DCHECK_EQ(val1, val2) CHECK_EQ(val1, val2)
#define DCHECK_NE(val1, val2) CHECK_NE(val1, val2)
#define DCHECK_LE(val1, val2) CHECK_LE(val1, val2)
#define DCHECK_LT(val1, val2) CHECK_LT(val1, val2)
#define DCHECK_GE(val1, val2) CHECK_GE(val1, val2)
#define DCHECK_GT(val1, val2) CHECK_GT(val1, val2)
#define DCHECK_NOTNULL(val) CHECK_NOTNULL(val)
#define DCHECK_STREQ(str1, str2) CHECK_STREQ(str1, str2)
#define DCHECK_STRCASEEQ(str1, str2) CHECK_STRCASEEQ(str1, str2)
#define DCHECK_STRNE(str1, str2) CHECK_STRNE(str1, str2)
#define DCHECK_STRCASENE(str1, str2) CHECK_STRCASENE(str1, str2)

#else // NDEBUG

#define DLOG(severity) \
  true ? (void)0 : google::LogMessageVoidify() & LOG(severity)

#define DVLOG(verboselevel) \
  (true || !VLOG_IS_ON(verboselevel)) ? (void)0 : google::LogMessageVoidify() & LOG(INFO)

#define DLOG_IF(severity, condition) \
  (true || !(condition)) ? (void)0 : google::LogMessageVoidify() & LOG(severity)

#define DLOG_EVERY_N(severity, n) \
  true ? (void)0 : google::LogMessageVoidify() & LOG(severity)

#define DLOG_IF_EVERY_N(severity, condition, n) \
  (true || !(condition)) ? (void)0 : google::LogMessageVoidify() & LOG(severity)

#define DLOG_ASSERT(condition) \
  true ? (void)0 : LOG_ASSERT(condition)

// MSVC warning C4127: conditional expression is constant
#define DCHECK(condition)              \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK(condition)

#define DCHECK_EQ(val1, val2)          \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_EQ(val1, val2)

#define DCHECK_NE(val1, val2)          \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_NE(val1, val2)

#define DCHECK_LE(val1, val2)          \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_LE(val1, val2)

#define DCHECK_LT(val1, val2)          \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_LT(val1, val2)

#define DCHECK_GE(val1, val2)          \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_GE(val1, val2)

#define DCHECK_GT(val1, val2)          \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_GT(val1, val2)

// You may see warnings in release mode if you don't use the return
// value of DCHECK_NOTNULL. Please just use DCHECK for such cases.
#define DCHECK_NOTNULL(val) (val)

#define DCHECK_STREQ(str1, str2)       \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_STREQ(str1, str2)

#define DCHECK_STRCASEEQ(str1, str2)   \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_STRCASEEQ(str1, str2)

#define DCHECK_STRNE(str1, str2)       \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_STRNE(str1, str2)

#define DCHECK_STRCASENE(str1, str2)   \
  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
  while (false)                        \
    GLOG_MSVC_POP_WARNING()            \
  CHECK_STRCASENE(str1, str2)

#endif // NDEBUG

  // Log only in verbose mode.

#define VLOG(verboselevel) LOG_IF(INFO, VLOG_IS_ON(verboselevel))

#define VLOG_IF(verboselevel, condition) \
  LOG_IF(INFO, (condition) && VLOG_IS_ON(verboselevel))

#define VLOG_EVERY_N(verboselevel, n) \
  LOG_IF_EVERY_N(INFO, VLOG_IS_ON(verboselevel), n)

#define VLOG_IF_EVERY_N(verboselevel, condition, n) \
  LOG_IF_EVERY_N(INFO, (condition) && VLOG_IS_ON(verboselevel), n)

  namespace base_logging
  {

    // LogMessage::LogStream is a std::ostream backed by this streambuf.
    // This class ignores overflow and leaves two bytes at the end of the
    // buffer to allow for a '\n' and '\0'.
    class GOOGLE_GLOG_DLL_DECL LogStreamBuf : public std::streambuf
    {
    public:
      // REQUIREMENTS: "len" must be >= 2 to account for the '\n' and '\n'.
      LogStreamBuf(char *buf, int len)
      {
        setp(buf, buf + len - 2);
      }
      // This effectively ignores overflow.
      virtual int_type overflow(int_type ch)
      {
        return ch;
      }

      // Legacy public ostrstream method.
      size_t pcount() const { return pptr() - pbase(); }
      char *pbase() const { return std::streambuf::pbase(); }
    };

  } // namespace base_logging

  //
  // This class more or less represents a particular log message.  You
  // create an instance of LogMessage and then stream stuff to it.
  // When you finish streaming to it, ~LogMessage is called and the
  // full message gets streamed to the appropriate destination.
  //
  // You shouldn't actually use LogMessage's constructor to log things,
  // though.  You should use the LOG() macro (and variants thereof)
  // above.
  class GOOGLE_GLOG_DLL_DECL LogMessage
  {
  public:
    enum
    {
      // Passing kNoLogPrefix for the line number disables the
      // log-message prefix. Useful for using the LogMessage
      // infrastructure as a printing utility. See also the --log_prefix
      // flag for controlling the log-message prefix on an
      // application-wide basis.
      kNoLogPrefix = -1
    };

    // LogStream inherit from non-DLL-exported class (std::ostrstream)
    // and VC++ produces a warning for this situation.
    // However, MSDN says "C4275 can be ignored in Microsoft Visual C++
    // 2005 if you are deriving from a type in the Standard C++ Library"
    // http://msdn.microsoft.com/en-us/library/3tdb471s(VS.80).aspx
    // Let's just ignore the warning.
#ifdef _MSC_VER
#pragma warning(disable : 4275)
#endif
    class GOOGLE_GLOG_DLL_DECL LogStream : public std::ostream
    {
#ifdef _MSC_VER
#pragma warning(default : 4275)
#endif
    public:
      LogStream(char *buf, int len, int ctr)
          : std::ostream(NULL),
            streambuf_(buf, len),
            ctr_(ctr),
            self_(this)
      {
        rdbuf(&streambuf_);
      }

      int ctr() const { return ctr_; }
      void set_ctr(int ctr) { ctr_ = ctr; }
      LogStream *self() const { return self_; }

      // Legacy std::streambuf methods.
      size_t pcount() const { return streambuf_.pcount(); }
      char *pbase() const { return streambuf_.pbase(); }
      char *str() const { return pbase(); }

    private:
      LogStream(const LogStream &);
      LogStream &operator=(const LogStream &);
      base_logging::LogStreamBuf streambuf_;
      int ctr_;         // Counter hack (for the LOG_EVERY_X() macro)
      LogStream *self_; // Consistency check hack
    };

  public:
    // icc 8 requires this typedef to avoid an internal compiler error.
    typedef void (LogMessage::*SendMethod)();

    LogMessage(const char *file, int line, LogSeverity severity, int ctr,
               SendMethod send_method);

    // Two special constructors that generate reduced amounts of code at
    // LOG call sites for common cases.

    // Used for LOG(INFO): Implied are:
    // severity = INFO, ctr = 0, send_method = &LogMessage::SendToLog.
    //
    // Using this constructor instead of the more complex constructor above
    // saves 19 bytes per call site.
    LogMessage(const char *file, int line);

    // Used for LOG(severity) where severity != INFO.  Implied
    // are: ctr = 0, send_method = &LogMessage::SendToLog
    //
    // Using this constructor instead of the more complex constructor above
    // saves 17 bytes per call site.
    LogMessage(const char *file, int line, LogSeverity severity);

    // Constructor to log this message to a specified sink (if not NULL).
    // Implied are: ctr = 0, send_method = &LogMessage::SendToSinkAndLog if
    // also_send_to_log is true, send_method = &LogMessage::SendToSink otherwise.
    LogMessage(const char *file, int line, LogSeverity severity, LogSink *sink,
               bool also_send_to_log);

    // Constructor where we also give a vector<string> pointer
    // for storing the messages (if the pointer is not NULL).
    // Implied are: ctr = 0, send_method = &LogMessage::SaveOrSendToLog.
    LogMessage(const char *file, int line, LogSeverity severity,
               std::vector<std::string> *outvec);

    // Constructor where we also give a string pointer for storing the
    // message (if the pointer is not NULL).  Implied are: ctr = 0,
    // send_method = &LogMessage::WriteToStringAndLog.
    LogMessage(const char *file, int line, LogSeverity severity,
               std::string *message);

    // A special constructor used for check failures
    LogMessage(const char *file, int line, const CheckOpString &result);

    ~LogMessage();

    // Flush a buffered message to the sink set in the constructor.  Always
    // called by the destructor, it may also be called from elsewhere if
    // needed.  Only the first call is actioned; any later ones are ignored.
    void Flush();

    // An arbitrary limit on the length of a single log message.  This
    // is so that streaming can be done more efficiently.
    static const size_t kMaxLogMessageLen;

    // Theses should not be called directly outside of logging.*,
    // only passed as SendMethod arguments to other LogMessage methods:
    void SendToLog();          // Actually dispatch to the logs
    void SendToSyslogAndLog(); // Actually dispatch to syslog and the logs

    // Call abort() or similar to perform LOG(FATAL) crash.
    static void __attribute__((noreturn)) Fail();

    std::ostream &stream();

    int preserved_errno() const;

    // Must be called without the log_mutex held.  (L < log_mutex)
    static int64 num_messages(int severity);

    struct LogMessageData;

  private:
    // Fully internal SendMethod cases:
    void SendToSinkAndLog(); // Send to sink if provided and dispatch to the logs
    void SendToSink();       // Send to sink if provided, do nothing otherwise.

    // Write to string if provided and dispatch to the logs.
    void WriteToStringAndLog();

    void SaveOrSendToLog(); // Save to stringvec if provided, else to logs

    void Init(const char *file, int line, LogSeverity severity,
              void (LogMessage::*send_method)());

    // Used to fill in crash information during LOG(FATAL) failures.
    void RecordCrashReason(glog_internal_namespace_::CrashReason *reason);

    // Counts of messages sent at each priority:
    static int64 num_messages_[NUM_SEVERITIES]; // under log_mutex

    // We keep the data in a separate struct so that each instance of
    // LogMessage uses less stack space.
    LogMessageData *allocated_;
    LogMessageData *data_;

    friend class LogDestination;

    LogMessage(const LogMessage &);
    void operator=(const LogMessage &);
  };

  // This class happens to be thread-hostile because all instances share
  // a single data buffer, but since it can only be created just before
  // the process dies, we don't worry so much.
  class GOOGLE_GLOG_DLL_DECL LogMessageFatal : public LogMessage
  {
  public:
    LogMessageFatal(const char *file, int line);
    LogMessageFatal(const char *file, int line, const CheckOpString &result);
    __attribute__((noreturn)) ~LogMessageFatal();
  };

  // A non-macro interface to the log facility; (useful
  // when the logging level is not a compile-time constant).
  inline void LogAtLevel(int const severity, std::string const &msg)
  {
    LogMessage(__FILE__, __LINE__, severity).stream() << msg;
  }

// A macro alternative of LogAtLevel. New code may want to use this
// version since there are two advantages: 1. this version outputs the
// file name and the line number where this macro is put like other
// LOG macros, 2. this macro can be used as C++ stream.
#define LOG_AT_LEVEL(severity) google::LogMessage(__FILE__, __LINE__, severity).stream()

  // A small helper for CHECK_NOTNULL().
  template <typename T>
  T *CheckNotNull(const char *file, int line, const char *names, T *t)
  {
    if (t == NULL)
    {
      LogMessageFatal(file, line, new std::string(names));
    }
    return t;
  }

  // Allow folks to put a counter in the LOG_EVERY_X()'ed messages. This
  // only works if ostream is a LogStream. If the ostream is not a
  // LogStream you'll get an assert saying as much at runtime.
  GOOGLE_GLOG_DLL_DECL std::ostream &operator<<(std::ostream &os,
                                                const PRIVATE_Counter &);

  // Derived class for PLOG*() above.
  class GOOGLE_GLOG_DLL_DECL ErrnoLogMessage : public LogMessage
  {
  public:
    ErrnoLogMessage(const char *file, int line, LogSeverity severity, int ctr,
                    void (LogMessage::*send_method)());

    // Postpends ": strerror(errno) [errno]".
    ~ErrnoLogMessage();

  private:
    ErrnoLogMessage(const ErrnoLogMessage &);
    void operator=(const ErrnoLogMessage &);
  };

  // This class is used to explicitly ignore values in the conditional
  // logging macros.  This avoids compiler warnings like "value computed
  // is not used" and "statement has no effect".

  class GOOGLE_GLOG_DLL_DECL LogMessageVoidify
  {
  public:
    LogMessageVoidify() {}
    // This has to be an operator with a precedence lower than << but
    // higher than ?:
    void operator&(std::ostream &) {}
  };

  // Flushes all log files that contains messages that are at least of
  // the specified severity level.  Thread-safe.
  GOOGLE_GLOG_DLL_DECL void FlushLogFiles(LogSeverity min_severity);

  // Flushes all log files that contains messages that are at least of
  // the specified severity level. Thread-hostile because it ignores
  // locking -- used for catastrophic failures.
  GOOGLE_GLOG_DLL_DECL void FlushLogFilesUnsafe(LogSeverity min_severity);

  //
  // Set the destination to which a particular severity level of log
  // messages is sent.  If base_filename is "", it means "don't log this
  // severity".  Thread-safe.
  //
  GOOGLE_GLOG_DLL_DECL void SetLogDestination(LogSeverity severity,
                                              const char *base_filename);

  //
  // Set the basename of the symlink to the latest log file at a given
  // severity.  If symlink_basename is empty, do not make a symlink.  If
  // you don't call this function, the symlink basename is the
  // invocation name of the program.  Thread-safe.
  //
  GOOGLE_GLOG_DLL_DECL void SetLogSymlink(LogSeverity severity,
                                          const char *symlink_basename);

  //
  // Used to send logs to some other kind of destination
  // Users should subclass LogSink and override send to do whatever they want.
  // Implementations must be thread-safe because a shared instance will
  // be called from whichever thread ran the LOG(XXX) line.
  class GOOGLE_GLOG_DLL_DECL LogSink
  {
  public:
    virtual ~LogSink();

    // Sink's logging logic (message_len is such as to exclude '\n' at the end).
    // This method can't use LOG() or CHECK() as logging system mutex(s) are held
    // during this call.
    virtual void send(LogSeverity severity, const char *full_filename,
                      const char *base_filename, int line,
                      const struct ::tm *tm_time,
                      const char *message, size_t message_len) = 0;

    // Redefine this to implement waiting for
    // the sink's logging logic to complete.
    // It will be called after each send() returns,
    // but before that LogMessage exits or crashes.
    // By default this function does nothing.
    // Using this function one can implement complex logic for send()
    // that itself involves logging; and do all this w/o causing deadlocks and
    // inconsistent rearrangement of log messages.
    // E.g. if a LogSink has thread-specific actions, the send() method
    // can simply add the message to a queue and wake up another thread that
    // handles real logging while itself making some LOG() calls;
    // WaitTillSent() can be implemented to wait for that logic to complete.
    // See our unittest for an example.
    virtual void WaitTillSent();

    // Returns the normal text output of the log message.
    // Can be useful to implement send().
    static std::string ToString(LogSeverity severity, const char *file, int line,
                                const struct ::tm *tm_time,
                                const char *message, size_t message_len);
  };

  // Add or remove a LogSink as a consumer of logging data.  Thread-safe.
  GOOGLE_GLOG_DLL_DECL void AddLogSink(LogSink *destination);
  GOOGLE_GLOG_DLL_DECL void RemoveLogSink(LogSink *destination);

  //
  // Specify an "extension" added to the filename specified via
  // SetLogDestination.  This applies to all severity levels.  It's
  // often used to append the port we're listening on to the logfile
  // name.  Thread-safe.
  //
  GOOGLE_GLOG_DLL_DECL void SetLogFilenameExtension(
      const char *filename_extension);

  //
  // Make it so that all log messages of at least a particular severity
  // are logged to stderr (in addition to logging to the usual log
  // file(s)).  Thread-safe.
  //
  GOOGLE_GLOG_DLL_DECL void SetStderrLogging(LogSeverity min_severity);

  //
  // Make it so that all log messages go only to stderr.  Thread-safe.
  //
  GOOGLE_GLOG_DLL_DECL void LogToStderr();

  //
  // Make it so that all log messages of at least a particular severity are
  // logged via email to a list of addresses (in addition to logging to the
  // usual log file(s)).  The list of addresses is just a string containing
  // the email addresses to send to (separated by spaces, say).  Thread-safe.
  //
  GOOGLE_GLOG_DLL_DECL void SetEmailLogging(LogSeverity min_severity,
                                            const char *addresses);

  // A simple function that sends email. dest is a commma-separated
  // list of addressess.  Thread-safe.
  GOOGLE_GLOG_DLL_DECL bool SendEmail(const char *dest,
                                      const char *subject, const char *body);

  GOOGLE_GLOG_DLL_DECL const std::vector<std::string> &GetLoggingDirectories();

  // For tests only:  Clear the internal [cached] list of logging directories to
  // force a refresh the next time GetLoggingDirectories is called.
  // Thread-hostile.
  void TestOnly_ClearLoggingDirectoriesList();

  // Returns a set of existing temporary directories, which will be a
  // subset of the directories returned by GetLogginDirectories().
  // Thread-safe.
  GOOGLE_GLOG_DLL_DECL void GetExistingTempDirectories(
      std::vector<std::string> *list);

  // Print any fatal message again -- useful to call from signal handler
  // so that the last thing in the output is the fatal message.
  // Thread-hostile, but a race is unlikely.
  GOOGLE_GLOG_DLL_DECL void ReprintFatalMessage();

  // Truncate a log file that may be the append-only output of multiple
  // processes and hence can't simply be renamed/reopened (typically a
  // stdout/stderr).  If the file "path" is > "limit" bytes, copy the
  // last "keep" bytes to offset 0 and truncate the rest. Since we could
  // be racing with other writers, this approach has the potential to
  // lose very small amounts of data. For security, only follow symlinks
  // if the path is /proc/self/fd/*
  GOOGLE_GLOG_DLL_DECL void TruncateLogFile(const char *path,
                                            int64 limit, int64 keep);

  // Truncate stdout and stderr if they are over the value specified by
  // --max_log_size; keep the final 1MB.  This function has the same
  // race condition as TruncateLogFile.
  GOOGLE_GLOG_DLL_DECL void TruncateStdoutStderr();

  // Return the string representation of the provided LogSeverity level.
  // Thread-safe.
  GOOGLE_GLOG_DLL_DECL const char *GetLogSeverityName(LogSeverity severity);

  // ---------------------------------------------------------------------
  // Implementation details that are not useful to most clients
  // ---------------------------------------------------------------------

  // A Logger is the interface used by logging modules to emit entries
  // to a log.  A typical implementation will dump formatted data to a
  // sequence of files.  We also provide interfaces that will forward
  // the data to another thread so that the invoker never blocks.
  // Implementations should be thread-safe since the logging system
  // will write to them from multiple threads.

  namespace base
  {

    class GOOGLE_GLOG_DLL_DECL Logger
    {
    public:
      virtual ~Logger();

      // Writes "message[0,message_len-1]" corresponding to an event that
      // occurred at "timestamp".  If "force_flush" is true, the log file
      // is flushed immediately.
      //
      // The input message has already been formatted as deemed
      // appropriate by the higher level logging facility.  For example,
      // textual log messages already contain timestamps, and the
      // file:linenumber header.
      virtual void Write(bool force_flush,
                         time_t timestamp,
                         const char *message,
                         int message_len) = 0;

      // Flush any buffered messages
      virtual void Flush() = 0;

      // Get the current LOG file size.
      // The returned value is approximate since some
      // logged data may not have been flushed to disk yet.
      virtual uint32 LogSize() = 0;
    };

    // Get the logger for the specified severity level.  The logger
    // remains the property of the logging module and should not be
    // deleted by the caller.  Thread-safe.
    extern GOOGLE_GLOG_DLL_DECL Logger *GetLogger(LogSeverity level);

    // Set the logger for the specified severity level.  The logger
    // becomes the property of the logging module and should not
    // be deleted by the caller.  Thread-safe.
    extern GOOGLE_GLOG_DLL_DECL void SetLogger(LogSeverity level, Logger *logger);

  }

  // glibc has traditionally implemented two incompatible versions of
  // strerror_r(). There is a poorly defined convention for picking the
  // version that we want, but it is not clear whether it even works with
  // all versions of glibc.
  // So, instead, we provide this wrapper that automatically detects the
  // version that is in use, and then implements POSIX semantics.
  // N.B. In addition to what POSIX says, we also guarantee that "buf" will
  // be set to an empty string, if this function failed. This means, in most
  // cases, you do not need to check the error code and you can directly
  // use the value of "buf". It will never have an undefined value.
  // DEPRECATED: Use StrError(int) instead.
  GOOGLE_GLOG_DLL_DECL int posix_strerror_r(int err, char *buf, size_t len);

  // A thread-safe replacement for strerror(). Returns a string describing the
  // given POSIX error code.
  GOOGLE_GLOG_DLL_DECL std::string StrError(int err);

  // A class for which we define operator<<, which does nothing.
  class GOOGLE_GLOG_DLL_DECL NullStream : public LogMessage::LogStream
  {
  public:
    // Initialize the LogStream so the messages can be written somewhere
    // (they'll never be actually displayed). This will be needed if a
    // NullStream& is implicitly converted to LogStream&, in which case
    // the overloaded NullStream::operator<< will not be invoked.
    NullStream() : LogMessage::LogStream(message_buffer_, 1, 0) {}
    NullStream(const char * /*file*/, int /*line*/,
               const CheckOpString & /*result*/) : LogMessage::LogStream(message_buffer_, 1, 0) {}
    NullStream &stream() { return *this; }

  private:
    // A very short buffer for messages (which we discard anyway). This
    // will be needed if NullStream& converted to LogStream& (e.g. as a
    // result of a conditional expression).
    char message_buffer_[2];
  };

  // Do nothing. This operator is inline, allowing the message to be
  // compiled away. The message will not be compiled away if we do
  // something like (flag ? LOG(INFO) : LOG(ERROR)) << message; when
  // SKIP_LOG=WARNING. In those cases, NullStream will be implicitly
  // converted to LogStream and the message will be computed and then
  // quietly discarded.
  template <class T>
  inline NullStream &operator<<(NullStream &str, const T &) { return str; }

  // Similar to NullStream, but aborts the program (without stack
  // trace), like LogMessageFatal.
  class GOOGLE_GLOG_DLL_DECL NullStreamFatal : public NullStream
  {
  public:
    NullStreamFatal() {}
    NullStreamFatal(const char *file, int line, const CheckOpString &result) : NullStream(file, line, result) {}
    __attribute__((noreturn)) ~NullStreamFatal() throw() { _exit(1); }
  };

  // Install a signal handler that will dump signal information and a stack
  // trace when the program crashes on certain signals.  We'll install the
  // signal handler for the following signals.
  //
  // SIGSEGV, SIGILL, SIGFPE, SIGABRT, SIGBUS, and SIGTERM.
  //
  // By default, the signal handler will write the failure dump to the
  // standard error.  You can customize the destination by installing your
  // own writer function by InstallFailureWriter() below.
  //
  // Note on threading:
  //
  // The function should be called before threads are created, if you want
  // to use the failure signal handler for all threads.  The stack trace
  // will be shown only for the thread that receives the signal.  In other
  // words, stack traces of other threads won't be shown.
  GOOGLE_GLOG_DLL_DECL void InstallFailureSignalHandler();

  // Installs a function that is used for writing the failure dump.  "data"
  // is the pointer to the beginning of a message to be written, and "size"
  // is the size of the message.  You should not expect the data is
  // terminated with '\0'.
  GOOGLE_GLOG_DLL_DECL void InstallFailureWriter(
      void (*writer)(const char *data, int size));
}

#endif // _LOGGING_H_
